Internal combustion engine



' Dec. 4, 1934.

R. A. MIDGLEY INTERNAL COMBUSTION ENGINE Filed Sept. 14, 1951 5 Sheets-Sheet 1 Dec. 4, 1934.

R. A. MIDGLEY INTERNAL COMBUSTION ENGINE Filed Sept. 14, 1931 ,7 ZLG. Z

| 73 y J5 1 E 64 I 72 5 Sheets-Sheet 2 INTERNAL COMBUSTION ENGINE Z wm m Patented Dec. 4, 19 34 UNITED STATES PATENT OF 1,983,237 INTERNAL COMBUSTION ENGINE Roy A. Midgley, Las Vegas. Nev. ApplicationSeptember 14; 1931, Serial no. 562,778 '1 Claims. (01. 123-45 This invention relates to the operation and controlof internal combustion engines, particularly automotive vehicle enginesof the four cycle type having cam shaft valve operation.

One object is the provision of a motor capable of operation either at high compression for speed and heavy duty or at lower compression for normal speeds, idling or coasting.

Another object is the provision in such a motor of means selectively operable for changing from high to low compression or vice versa during operation urther object is the provision of manually operable means for changing the valve timing of an; engine during operation thereof to vary the power. output, as well as to provide a novel valve arrangement for engines of the internal com bust ion type. Other objects will be apparent from thedescription. The herein disclosed embodiment constitutes the best means I have thus fardevised for reducing the invention to practice.

In the drawings: 7 Figure 1 is a fragmentary side elevation of an engine as constructed in accordance with the invention.

Figure2 isa vertical section through a cylinder substantially on the line 2-2 of Figure 1.

Figure 3 is an end view of a cam arrangement 3G for operating certain of the valves.

Figure 4 is a side elevation of a cam as shown in Figure .3 and illustrating in dotted lines the shifted position of the cam. 1

Figure 5 is an end view of another cam arrangement for operating a different set of valves.

Figure 6 is a side elevation of the cam arrangemerit shown in Figure 5. V

Figure 7 is a perspective illustrating the assembly of. the cam shaft shiftingmeans.

0 Figure 8 is a fragmentary section through a cylinder as shown in Figure 2 and illustrating the arrangement of parts with the piston at bottom center. 7 V

Figure 9 is a section taken substantially on the line 9--9 of Figure 1 and illustrating the air valve as in open position. l

Figure it) is a horizontal section substantially on the line 1010 of Fi ure 2.

Briefly described. the invention consists in providing a supplemental set of valvesopening to the bottom of a cylinder of an engine having the exhaust and intake valves located adjacent the head thereof and operated in a conventional manner from a crank shaftdisposed longitudi nal-ly of the engine. Each cylinder'is provided with two of the supplemental valves, one of which operates to admit a fuel charge beneath the piston and the other of which operates to admit air beneath the piston. These supplemental valves are controlled from camsdisposed on the same cam shaft which carries the cams for operating the regularintake and exhaust valves.

Means are provided for shifting the cam shaft longitudinally to change the timing and operation of the supplemental valves. By appropriate movement of the cam shaft the engine may be operated forhigh speeds and heavy duty by a maximum compression during which operation the fuel chargeis admitted both through the res- 7 0. ular inlet valves and the supplemental valves. With the cam shaft shifted to another position the engine operates on minimum compression wherein the fuel supply and exhaust are only through the regular valves adjacent the cylinder head. i

The engine is provided with means for scavenging thecylinders by air compressed through action of the pistons within the cylinders operating in conjunction with the supplemental valves. By 80, this arrangement it is possible to vary the power output of an engine merely by shifting the valve operating cam shaft, thus providing a power factor variation v means acting independently of any gear shift arrangement with which the engine 5 may be associated.

As shown in Figure l the engine consists of a block of parallel cylinders 11 which may be cast en bloc and which are provided with a cylinder head casting 12. The block of cylinders 11 seats 9c upon a lower cylinder block 12 formed as a part of the crank casing 13. It will be apparent that each cylinder of. the engine consists of an upper portionsll and a lower portion 12. A cam shaft 14 extends at one side longitudinally of the engine block and carries a plurality of cams for operating the stems 15 and 16 which are respectively the fuel inlet and exhaust valve stems. The valves operated from the stems 15 and 16 are disposed in the usual manner to open into the 109 cylinder head 12. The stems 15 are driven by regular cams 1'7 and the stems 16 by regular cams 18 keyed to the shiftable shaft 14. These cams 17 and 18 are conventional as to cam bearing surface, but are made somewhat more than twice the width of the ordinary cams in order to provide the proper camming surface in either of the two positions which the cam shaft 14 may assume when shifted. At its forward end the cam shaft 14 which is longitudinally slidable through its bearing brackets 19, has pivotal connection with one end of a rocking lever 20 fulcrumed intermediate its ends on a bracket 22 extending from the engine crank case and having its opposite end pivotally connected with a link rod 23 which is in turn pivotally connected with a foot pedal lever 24 fulcrumed intermediate its ends for rocking movement in a vertical plane on a bracket 25 having a swiveled mounting in a floor board 26 forming a part of a vehicle with which the engine is associated.

As best illustrated in Figure '7, the 'swiveled bracket 25 has fixed thereto a lateral arm 2'7 to the outer end of which is pivotally connected 2. control rod 28 leading to a throttle control, not shown, for the carburetor 29 shown in'Figure 2.

The foot pedal lever 24 is provided at its upper end with a toe rest 30 and adjacent its lower end with a heel rest 31. It will be apparent that as the pedal 24 is rocked in a vertical plane the cam shaft 14 will be shifted either forwardly or rearwardly along the engine block. When the pedal is moved through a vertical plane which is perpendicular to its plane of movement in shifting the cam shaft, it rocks through themedium of the swivel bracket 25 to elevate or depress the arm 27 and through this means influences the throttling of the engine through the operating control 28.

The cam shaft 14 has also keyed thereto a series of cams 32 and 33 which respectively operate the stems 34 and 35 of the supplemental air and fuel valves later to be described in detail. Figures 3 and 4 illustrate the construction of the cams 33 wherein as shown each cam indicated by the general reference character 33 is provided with the usual eccentric riser 36, and the cam body is provided at one side with an extension 37 concentric to the shaft 14. This extension 37 has a diameter which is considerably less than the rise of the cam 36 and the two cam bearing portions 36 and 37 are spaced by a sloping face portion 38 which provides a gradual inclined cam surface intermediate the eccentric portion 36 and the concentric portion 37 of the cam.

Cooperating with these cams are the stems 35 of the supplemental fuel intake valves, which stems are provided at their lower ends with forks 39 having journaled therebetween rollers 40 adapted to contact the cam surfaces and which rollers are provided with inclined face portions 41 having an angle of inclination corresponding to that of the inclined cam surface 38. The inclined faces 41 of the rollers are disposed at the side upon which the respective cams are shifted, as best illustrated in Figure 4.

I Figures 5 and 6 illustrate the construction of the cams generally indicated by the reference character 32 which control the operation of the supplemental air valves. Each of the cams 32 has a cam surface 42 concentric with the shaft 14 through a circumference of 270 degrees with a diameter equal that of the largest diameterof the cam 36. The remaining 90 degrees of circume ference for the cam 42 is formed as a chord to provide a flat bearing surface 43. The body of the cam is provided with an extension formed as a smaller circular cam surface 44 through a circumference of 270 degrees of a circle having a diameter equal to that of the cam 37 and concentric with the shaft 14. The remaining 90 degrees is formed as a riser having inclined side faces 45 and a peak 47 which is flush with the periphery of the cam 42. As best shown in Figure 5, the peak 47 of the cam '44 coincides with one end of the chordial surface 43 of the cam 42.' Between these two cams a sloping cam surface 43 is provided which surface acts as a spacer between the cams.

Cooperating with the earns 32 are the valve stems 34 which are provided at their lower ends with forks 49 between which are journaled bearing rollers 50 for contacting bearing surfaces. These rollers 50 have inclined bearing face portions 51 disposed on the side of shifting movement of the cams so that under the longitudinal shifting of the shaft 14 the sloping faces 51 engage the sloping faces 48 of the cams 32 to facilitate the shifting action.

The cylinder construction is best shown in Figures 2 and 9. Each cylinder consists of an upper section 11 and a bottom section 12 rising from the crankcase 13. Within the upper section is disposed a piston 52 having a central depending tubular skirt 53 in the lower open end of which the wrist pin 54 makes connection in the usual manner with the conventional connecting rod assembly 55 from the engine crank shaft 56.

At its upper end the cylinder section 12 is provided with an annular web 57 which closes the top of the section except for a central bearing aperture through which the skirt 53 of the piston is guided. At its lower end the skirt 53 carries a cross head 58 having slidable bearing against the walls of the section 12. The head of the piston 52 has a depending annular rim flange 59 concentric with the skirt 53 and spaced therefrom to form an annular socket 60 in the under side of the head of the piston. Cooperating with this socket is a collar 61 secured by appropriate means to the web 57 and centrally apertured to provide a bearing for the piston skirt 53. The upper face of the collar 61 is shaped to conform with the recess 60 in the piston head so that when the piston is at bottom center as indicated in Figure 8, the head will be substantially in flush engagement over the collar. The collar 61 is provided with a by-pass channel 62 for a purpose to be described.

The Wall of each cylinder is formed with a lateral by-pass chamber 63 which opens into the upper cylinder section 11 above the web 57 of the lower section 12. The top wall 64 of the by-pass chamber occupies a horizontal plane which is spaced sufficiently above the web 57 to provide a clearance between the said top wall and the top face of the piston 52 when the piston is at its bottom center as shown in Figure 8. The bottom of the by-pass chamber is formed with guides 65, through which operate the supplemental valve stems 34 and 35 which stems carry at their upper ends respectively poppet valves 66 and 67.

The external wall of the by-pass chamber, is formed with an indented recess extending from top to bottom to provide a clearance for the stem 15 of the regular fuel intake valve 63 which opens into the cylinder head 12. Extending transversely and horizontally acrossthe by-pass chamber is a pipe 69 closed at its inner end by the cylinder wall and open at its outer end 70 to vthe atmosphere. The air valve 66 seats in the bottom of this air supply pipe 69. At the one side of the by-pass chamber a similar supply pipe 71 extends thereacross, having its inner end closed by the cylinder wall and opening at its outer end to a connection with a fuel supply manifold '72 leading from the carburetor 29. The manifold '72 also supplies fuel to a chamber 73 beneath the regular intake valve 68 of the engine. The valve 67 has a seat in the bottom wall of the supply pipe '71. The regular engine exhaust valve 74 operated from the stem 16 opens to a chamber 75 which is mea er an exhaust manifold,

ice, speed and heavy duty, when the piston is at top center on the compression stroke, as shown in Figure 2, the charge. is fired from spark plug 76. As the piston. travels. down on its power stroke the exhaust valve in the cylinder head opens in regular time. When bottom center is reached and the piston begins its discharge stroke, the riser 36 of cam 33 opens the lower intake valve 67 allowing a charge of gas to be drawn into the by-pass chamber 63 and into the cylinder 11 beneath the ascending. piston.

As the piston reaches top center on the discharge stroke the lower fuel intake valve 67 closes and the upper fuel intake valve opens. On its downward suction stroke the piston draws gas into the upper part of the cylinder and compresses gas in the lower part above web 57 and collar 61 and in by-pass chamber 63. On this stroke as the piston nears bottom center the upper intake valve 68 closes, andgas trapped in the piston head socket is discharged through passage 62 of the collar 61 into the by-pass chamber. When the piston passes below the top wall 64 of the by-pass chamber the gas compressed therein passes into the cylinder above the piston, mingling with the gas drawn through valve 68 to increase the charge volume.

When the piston begins its upward travel on the compression stroke cam 32 through its peak 47 causes air valve 66 to open, admitting air from pipe 69 to the by-pass chamber and below the piston. This air valve 66 closes as thepiston reaches top center on its compression stroke, and as the piston descends on'the power stroke the air is compressed beneath the piston and in the by-pass chamber from whence it discharges into the cylinder to scavenge the exploded gas as the piston passes below the top wall 64 of the by-pass chamber. From this point the cycle of operation is repeated as described.

In this operatin phase of the engine both the lower fuel valve 67 and the air inlet valve 66 are open during one cycle only of the four. The cam shaft 14 is in a position to dispose the cams so that the bearing rollers 40 on the valve stems 35 of the lower fuel intake valves engage the cam surfaces 36 of the cams 33 while the rollers 50 on the valve stems 34 of the air inlet valves engage the cam surfaces 44-45-47 of the cams 32.

When it is desired to operate the engine on low compression for light duty or coasting, the pedal 24 is rocked to shift the cam shaft longitudinally through the connections previously described whereupon the cams 32 and33 will be moved to dispose the respective valve stem rollers 50 and 40 in engagement with the cam surfaces 4243, and 37. The double width of the cams 17 and 18 allows a continuous operation of the regular intake and exhaust valves without any change in timing as the cam shaft is shifted.

In this operating phase of the engine the lower der, fuel supply and exhaust valves adjacent the I headthereof, a piston in said cylinder, a by-pass in the wall of the cylinder adjacent its bottom, a supplemental fuelsupply valve in said by-pass an. air inlet valve in. said by-pass, a cam shaft, means for axially shifting said cam shaft, and cams on said shaft arranged for. operating all of said valves in timed relation in. one position of the cam shaft and for operating only three of said valves in a different timed relation in another position of the cam shaft.

2. In an internal combustion engine, a cylinder having fuel intake and exhausts valves adjacent the head thereof, a piston in said cylinder, an annular web closing said cylinder beneath the bottom center of the piston, a depending skirt on said piston and slidable through said web, a by-pass chamber on the cylinder wall adjacent said web, a fuel intake valve in said chamber, an air inlet valve in said chamber, a common means for operating all of said valves in timed relation, and means for shifting said common operating means to vary the timed relation of the valves in said chamber with respect to the valves adjacent the cylinder head while the engine is turning over.

3. In a four cycle engine provided with cam operated intake and exhaust valves normally operated in timed relation, supplemental intake valves, air inlet valves, a shiftable cam shaft, means for axially shifting said shaft, and cams on said shaft for operating all of said valves, the cams for said supplemental intake valves being arranged to maintain their valves continuously closed in one position of the cam shaft and open through one cycle only in another position of the cam shaft.

4. In a four cycle engine provided with cam operated intake and exhaust valves normally operated in timed relation, supplemental intake valves, air inlet valves, a shiftable cam shaft, means for axially shifting said shaft, and cams on said shaft for operating all of said valves,

the cams for said air inlet valves being arranged to maintain their valves open through three cycles only in one position of the cam shaft and,

open through one cycle only in another position of the cam shaft.

5. In an internal combustion engine a cylinder, a fuel supply valve and an exhaust valve adjacent the head thereof, a piston in said cylinder,

a by-pass on the wall of said cylinder and opening to the interior thereof at a point between top center and bottom center of the piston, a supplemental fuel supply valve in said by-pass, an

air inlet valve in said by-pass, a cam shaft, cams on said shaft for operating all of said valves, and

means for selective alteration of the timing of said supplemental fuel supply valve and air inlet valve with respect to the fuel supply valve and the exhaust valve adjacent the cylinder head while the engine is turning over.

6. In an internal combustion engine, a cylinder, an upper fuel supply valve opening to the cylinder at one end, a lower fuel supply valve opening to the cylinder at its opposite end, an exhaust valve, an air inlet valve, a cam shaft, a cam on said shaft for each of said valves, the cams for said lower supply valve and the air inlet valve having portions thereof formed to operate said valves in various timed relationship with respect to the other valves, and means for shifting said cam shaft to change the bearing surface of said last named cams presented for operating their respective valves, said shifting cylinder, a socket in the under face of the piston head conforming to the configuration of said collar, a by-pass on the cylinder wall adjacent said Web and collar, and said collar having a vent passage therein from its upper face to a side face thereof for communication with said by-pass.

ROY A. MIDGLEY. 

